Conventionally, when forming an insulating layer having a high pressure resistance property or an excellent leak property against a gate oxide film of a semiconductor device represented as a LSI (Large Scale Integrated Circuit) or a CCD (Charge Coupled Device) and a MOS (Metal Oxide Semiconductor) transistor, a thermal CVD (Chemical Vapor Deposition) method is generally used. However, if a silicon oxide film having a high insulation property is formed by the thermal CVD method, a silicon substrate needs to be exposed to high temperature. In this case, if a conductive layer is formed on the silicon substrate by using a material having a relatively low melting point, such as metal having a low melting point, or a high molecular compound, the metal having a low melting point may be melted.
Recently, as devices become highly integrated, there is required a high-quality film property having a good step coverage or uniformity against a three-dimensional structure and no impurities or physical defects within an insulating film and at an interface. As one of efficient methods for satisfying this requirement, an ALD (Atomic Layer Deposition) method has been known. In the ALD method, a reactant gas in an atomic unit is supplied regularly to a surface of a substrate to form a film, and a film thickness is controlled with high accuracy. However, as compared to a property of a film formed by the thermal CVD, a property of a film formed by the ALD method has bad pressure resistance property or bad leak property. As a method for solving these problems and efficiently forming a high-quality film, a PE-ALD (Plasma-Enhanced ALD) method has drawn attention (May 15, 2008 ASM Semi Mfg China ALD Article.pdf (Non-Patent Document 1)).    Non-Patent Document 1: May 15, 2008 ASM Semi Mfg China ALD Article.pdf